1. Field of the Invention
The present general inventive concept relates to a toner monitoring network printer system and a method of monitoring a toner cartridge thereof. More particularly, the present general inventive concept relates to a toner monitoring network printer system which is capable of broadcasting toner cartridge information anytime during the printing operations of network printers, thereby preventing a failure in accurately checking a toner residue value of a toner cartridge when a power supply is interrupted intentionally or accidentally.
2. Description of the Related Art
In general, a laser beam printer (hereinafter referred to as ‘printer’) performs a printing operation using an electrophotographic processing method. For the printing operation, the printer evenly charges a surface of an organic photoconductive drum using a rotating charge roller, and forms an electrostatic latent image, which is identical to an image output from a PC, on the charged surface of the organic photoconductive drum via a laser scan unit (LSU) which converts a digital signal to light. The electrostatic latent image formed on the organic photoconductive drum is developed by a toner via a developing device and is converted into a visible image. When a paper sheet, which is picked-up from a paper cassette by a pickup roller and fed into the printer, passes between transfer rollers, a backside surface of the paper sheet is charged with an opposite electric charge so that the visible image is transferred from the organic photoconductive drum to the paper sheet. The transferred image is fused onto the paper sheet due to heat and pressure as the paper sheet passes between a heating roller and a squeeze roller. The paper sheet is discharged along a pre-set conveyance path via a first discharge roller or a second discharge roller in a forward direction or a backward direction.
As shown in FIG. 1, a toner cartridge 20 mounted in the printer as described above comprises a cartridge memory 21 for storing information about the toner cartridge, and a memory module 23 for updating the information stored in the cartridge memory 21.
The information stored in the cartridge memory 21 is referred to as Cartridge Replace Unit Memory (CRUM) information, and it includes a serial number of the toner cartridge, a supplier of the toner cartridge, a toner residue value, and a toner state. Information about the serial number and supplier of the toner cartridge is not changeable because it is fixed during the manufacturing or supplying of the toner cartridge. However, the toner residue value of the toner cartridge is changeable in that it changes every time that a printing operation is performed at the request of a user. Based on the changed toner residue, the memory module 23 updates the information about the toner cartridge stored in the cartridge memory 21, including the toner residue value.
The toner residue value is computed by the printer. In order to manage the toner cartridge 20, as shown in FIG. 2, the printer comprises a printed page counter 135 for counting the number of printed pages, a toner residue computing part 137 for computing a toner residue value of the toner cartridge based on the number of printed pages, a non-volatile random access memory (NVRAM) 133 for storing the number of printed pages counted by the printed page counter 135 and the toner residue value computed by the toner residue computing part 137, an authentication part 132 for determining whether the mounted toner cartridge 20 is a genuine product, and a central processing device 131 informing a user of the toner residue value computed by the toner residue computing part 137 and stopping the printing operation when there is no toner residue remaining.
The toner residue computing part 137 obtains a total amount of consumed toner by multiplying an average amount of toner consumed per one paper sheet by the number of printed pages as counted by the printed page counter 135, and then, obtains the toner residue value by subtracting the total amount of consumed toner from a full amount of toner. The average amount of toner consumed per one paper sheet is a value that is determined through experiment and stored in memory.
Operation of the printer as described above is described hereinbelow with reference to FIG. 3.
When power is supplied to the printer (step S310), the central processing device 131 reads the CRUM information from the toner cartridge 20 (step S320), and the authentication part 132 determines whether the toner cartridge 20 is a genuine product based on the CRUM information (step S330). If the toner cartridge 20 is determined to be a genuine product by the authentication part 132, the central processing device 131 controls such that a printing operation is performed (step S340), and if not, it controls such that the printing operation is not performed (step S335).
Next, the central processing device 131 controls the printed page counter 135 and the toner residue computing part 137, respectively, to continuously count the number of printed pages and compute the toner residue value of the toner cartridge 20 (steps S350 and S360). The central processing device 131 stores the computed toner residue value in the NVRAM 133 (step S370). Next, when the printing operation is completed and a printer engine stops its operation (step S380), the central processing device 131 provides the toner cartridge 20 with the resulting toner residue value. The memory module 23 of the toner cartridge 20 stores in the cartridge memory 21 the resulting toner residue value provided from the printer to update the information about the toner residue (step S390).
The information about the toner residue stored in the cartridge memory 21 is maintained until it is updated as the next printing operation is performed. The CRUM information stored in the cartridge memory 21 is maintained even when the toner cartridge 20 is dismounted from the printer. On the other hand, the information stored in the NVRAM 133 of the printer disappears when the toner cartridge 20 is replaced with a new one. That is, the information stored the NVRAM 133 of the printer is updated with information on a newly mounted toner cartridge, and the toner residue computing part 137 computes a new toner residue value based on the number of pages printed by the newly mounted toner cartridge 20. The computed result of the toner residue is stored in both the NVRAM 133 of the printer and the newly mounted toner cartridge 20.
As described above, the printer stores only the information about the currently-mounted toner cartridge 20. The printer continuously computes the toner residue value during the printing operation, but cannot provide the resulting toner residue value to the toner cartridge 20 until the printing operation is completed. Therefore, if the printer's power supply is suddenly interrupted during the printing operation or if a user turns off the power intentionally to replace the toner cartridge 20 with a new one, the resulting toner residue value cannot be provided to the toner cartridge 20.
Monitoring the toner residue value is useful with respect to preventing the use of illegally-distributed toner or refill-dedicated toner made by a different manufacture. Users sometimes use illegally-distributed toner or a refill-dedicated toner instead of replacing spent cartridges with genuine toner cartridges 20. If the illegally-distributed toner or the refill-dedicated toner made by the different manufacturer is used, the printer, which is optimized for use with genuine toner, cannot achieve an optimal printing performance. Consequently, print quality deteriorates. Also, the illegally-distributed toner or the refill dedicated toner made by the different manufacturer causes an increase in the waste of toner remaining on the organic photoconductive drum, and thus, increases the waste toner collected in a waste-toner collection receptacle. However, because the waste-toner collection receptacle is suitable in size to the genuine toner, the waste toner overflows the waste-toner collection receptacle, which causes contamination to parts of the printer and thus reduces the lifespan of the printer and the parts of the printer.
In order to solve problems arising from the use of the illegally-distributed toner or the refill-dedicated toner, the printer takes an authentication procedure with respect to the toner cartridge 20 when power is supplied or the toner cartridge 20 is replaced with a new one. Specifically, when power is supplied to the printer or the toner cartridge is replaced with a new one, the printer reads the CRUM information from the cartridge memory 21 of the toner cartridge 20 to determine whether the toner cartridge 20 is a genuine product, and also whether the toner cartridge 20 has been refilled. If the toner cartridge is not determined to be a genuine product or it has been refilled, the printer controls such that the printing operation is not performed.
Whether the toner cartridge 20 is a genuine product is determined by identifying a serial number of the toner cartridge 20. Whether the toner cartridge 20 has been refilled is determined based on the toner residue value. As described above, the printer computes the toner residue value based on the number of printed pages and stores the computed toner residue value in the cartridge memory 21 of the toner cartridge 20. Therefore, even if the toner cartridge 20 is refilled, the CRUM information stored in the cartridge memory 21 still indicates that there is no toner remaining in the toner cartridge 20. Accordingly, the central processing device 131 determines that there is no toner residue in the toner cartridge 20 and stops the printing operation.
As described above, when the power supply is suddenly interrupted or a user turns off the power intentionally, the printer cannot provide the toner residue value as computed by the printer to the toner cartridge 20.
Sometimes a user intentionally turns off the power or dismounts the toner cartridge 20 before the printing operation is completely finished in order to refill the toner cartridge. Once this occurs, the toner cartridge 20 cannot be provided with the toner residue value according to the printing operation, and also, the CRUM information on the toner cartridge 20, including the toner residue value, is deleted. If the toner residue value is not recorded in the toner cartridge 20, the information stored in the cartridge memory 21 indicates that there is sufficient toner remaining in the toner cartridge 20, even if there is no toner remaining in the toner cartridge 20.
In this state, when a user refills the toner cartridge with the illegally-distributed toner or the refill-dedicated toner, the printer cannot recognize that the toner cartridge 20 has been refilled because the CRUM information of the toner cartridge 20 indicates there is toner remaining in the toner cartridge 20, and thus authenticates the toner cartridge 20.
As described above, illegally-distributed toner or refill-dedicated toner causes the lifespan of the printer and component parts thereof to be shortened. Illegally-distributed toner or refill-dedicated toner also deteriorates print quality. Accordingly, it is desirable to update the information on the toner residue even when the user turns off the power to the printer intentionally or accidentally.